6-604.   Sole source procurement.
Any goods or services, which may not be procured by competitive means because of the existence of a single source or because of a proprietary product shall be exempt from the competitive bidding process; however, the procurement of such goods or services will be with the prior written approval of the city manager.
   (1)   Where a department of the city government has established a particular model/type of equipment for a specific application, subsequent additions to that system or parts required for maintenance and repair thereto, shall be classified as sole source procurement to insure that the integrity of the system is maintained.